1. Field of the Invention
This invention relates to electric power switches and to terminals for connecting such switches to electrical conductors, especially terminals for making quick connections, including connections to multiple wires, without the need for tools.
2. Background Information
Power switches used in electrical distribution systems, such as for instance, circuit breakers, transfer switches, disconnect switches, contacts, motor starters and the like, require connections for electrically connecting the power conductors of the switch to the electrical conductors of the distribution system. Typically, the power conductor of the switch is a rigid, flat conductor. A common connection for cable connected switches, that is switches connected to electrical cables or wires, is the collar terminal. The collar terminal has a cylindrical or square body with a transverse slot in which the flat power conductor of the switch and wire or cable are received, and a tapped bore into which a screw is threaded to clamp the wire or cable against the power conductor while also securing the collar to the power conductor. Typically, the collar terminal is received in a recess in a molded casing of the power switch.
In some applications, it is desirable to have a quick connection for connecting the wires or cables to the power conductors of the switch, preferably without the need of a tool such as a screwdriver, as is required for the collar terminal. In other applications, it is desirable to be able to easily connect multiple wires to the same power conductor, preferably without having to clamp multiple wires with a single collar connector.
Circuit breakers are available with quick connect terminals. The usual collar terminal is replaced by a terminal fabricated from sheet material having a number of male connectors projecting from edges of one face, and a common tang projecting from an edge of the opposite face and brazed or welded to the power conductor of the circuit breaker. Female clips on wires then slide onto the male connectors to provide multiple quick connections. However, the purchaser must specify the type of terminals wanted: either collar type or quick connect type. They are not interchangeable. Thus, the manufacturer must make and stock switches with each type of terminal connector and the purchaser must elect the switch with the desired terminals.
There is room for improvement, therefore, in terminals for electric power switches.
The invention provides an improved quick connect terminal for an electric power switch having a molded casing with a power conductor extending into an external terminal recess in the molded casing and a terminal connector connected to the power conductor in the terminal recess. The quick connect terminal comprises a molded housing having an open cavity and a mount removably mounting the molded housing to the molded casing of the power switch at the external recess. An electrically conductive terminal member has one end releasably secured to the power conductor by the terminal connector, and at a second end, at least one male termination terminating in the open cavity. The housing of the quick connect terminal has a cavity wall with a slot through which the at least one male termination extends into the open cavity. The terminal member can have a plurality of the male terminations, in which case the cavity wall has a plurality of slots so that the plurality of male terminations all extend into the open cavity. In the exemplary embodiment of the invention there are four male terminations in the open cavity.
The terminal member is a flat electrically conductive strip having a center section with the first end bent to form a tang extending transversely from one end of the center section in a first direction. The one or more male terminations extend transversely from the center section in a second direction opposite the first direction. These male terminations can extend from opposite side edges of the center section.
The molded housing of the quick connect terminal can have a retainer securing the terminal member to the molded housing. This retainer can be in the form of an opening in the center section of the terminal member and a pair of oppositely facing catches, preferably in the form of hooks molded on the cavity wall which flex to engage opposite edges of the opening in the terminal member. These hooks can be chamfered so that they deflect to engage the opening as the center section of the terminal member is pressed against the chamfered hooks.
The mount mounting the molded housing of the quick connect terminal to the molded casing of the power switch can include at least one compliant latch on the molded housing which engages a latch ledge molded into the external recess of the switch molded housing. In this regard, the external recess in the molded housing of the power switch can have an elongated opening and inwardly facing latch ledges on each side. In this case, the mount includes a pair of spaced apart compliant latches on the molded housing of the quick disconnect terminal having opposite facing latch hooks which engage the latch ledges. This pair of compliant latches can be cantilevered from and integrally molded with the molded housing. They can have opposite facing finger grips by which the pair of compliant latches are squeezed toward each other to release the molded housing from engagement with the molded casing of the power switch. The mount can further include a pair of compliant latches cantilevered from one end of the molded housing and at least one mounting hook extending adjacent the second end of the mold housing and engaging an abutment surface on the molded casing.
The invention also embraces an electric power switch which comprises a molded casing having an external recess, a power conductor projecting into the terminal recess and a collar terminal received in the terminal recess and having a terminal body with a transverse slot into which the power conductor extends. The terminal body also has a tapped longitudinal bore and a terminal screw threaded into the tapped longitudinal bore that clamps against the power conductor. The electric power switch further includes a quick connect terminal comprising an electrically conductive terminal member having a tang at one end and at least one male terminal adjacent a second end. The quick connect terminal further includes a molded housing having an open cavity into which the at least one male terminal projects with the tang projecting from the housing. The tang is removably received in the collar terminal and clamped against the power conductor by a terminal screw. The molded housing of the quick connect terminal can include a mount for removably securing the molded housing to the molded casing at the external terminal recess. This mount can include one or more compliant latches which engage latch ledges in the external recess of the power switch molded casing. In a particularly advantageous arrangement, a pair of compliant latches are cantilevered from one end of the molded housing and can be provided with finger grips for squeezing the compliant latches together to release them from the latch ledges in the recess in the power switch molded casing. In addition, the molded casing can have at least one mounting hook extending adjacent the opposite end of the molded housing and engaging an abutment surface on the molded casing of the power switch.
With the above arrangements, a single power switch can be provided either with a conventional terminal or a quick connect terminal. Hence, only one power switch need be stocked, and it can be provided by the manufacturer or can be field adapted to have either type of terminal connector.